Abstract

This report discusses a NIR analysis application of Thermomechanical pulp (TMP) properties measured with a TQA analyzer. TQA (Total Quality Analyzer) is ABB's measurement device that measures in-line the NIR spectra from the pulp flowing through the blow line of a TMP process. The main purpose of this work was to measure the freeness, strength properties (tear index, tensile index) and light scattering coefficient of the pulp using the NIR spectra. Data for the calibration of the measurements was collected during several test runs in a Finnish TMP plant. The calibrated measurements were also tested with independent test data. The calibration was done using the Partial Least Squares method.

Furthermore, the NIR spectra were measured from the hand sheets made for the laboratory analysis using a laboratory FT-IR analyzer. Correlations between the spectral analysis and several pulp characteristics were studied.